Examples of such special number calls include 9-1-1 calls for seeking emergency services and other abbreviated number calls for non-emergency special services, such as “N-1-1” systems. Examples of such N-1-1 systems include “3-1-1” (urgent but not emergency calls) and “5-1-1” (traffic inquiry calls). Special number calls may also include, by way of further example and not by way of limitation, abbreviated numbers for calling commercial services, such as “*820” (calling a radio station) or “GOTIX” (calling for tickets).
For purposes of illustration, by way of example and not by way of limitation, the present invention will be described in the context of an emergency service network in the United States, commonly referred to as a 9-1-1 network. The teachings of the present invention are equally applicable, useful and novel in other special number calling systems, such as maintenance service networks, college campus security networks, abbreviated number networks for calling commercial services and other networks.
Wireless E9-1-1 can be separated into Phase I and Phase II technologies. Phase I requires that a calling party's mobile telephone number and location of the cell site and sector from which the 9-1-1 call originated be delivered to a responding Public Safety Answering Point (PSAP; sometimes referred to as a Public Safety Answering Position). The mobile telephone number of the caller can be used by the PSAP to call back in the event that the connection is lost. The location of the cell site and cell sector assist in transferring the 9-1-1 call to another appropriate PSAP that may be advantageously located for providing required emergency services.
Phase II requires that the mobile telephone number and location (latitude and longitude) of the caller be delivered to the PSAP within a specified accuracy margin.
Call routing based on population can be relevant to the routing of Phase I wireless 9-1-1 calls. Once a PSAP has submitted a formal request for service from a Wireless Service Provider (WSP), the WSP has 180 days to deploy Phase I. If the WSP is unable to provide the service within the specified time frame, the Federal Communications Commission may levy fines.
The WSP and PSAP generally work closely to ensure the timely deployment of Phase I and may, during the planning process, provide documentation such as a map setting out jurisdictional boundaries of one or more PSAPs and a boundary map indicating cell towers and cell sectors.
Cell tower and cell sector location information, latitude, longitude, and cell sector radius are among data that may be obtained from a WSP. By way of example and not by way of limitation, data may be received in the form of an on-line spreadsheet such as an Excel® Spreadsheet. A Wireless Implementation Specialist (WIS) or other planner converts the data received in the spreadsheet into an on-line file (such as, by way of example and not by way of limitation, a file in “.dbf” format) and imports the information and data to a Geographic Information Service (GIS) file, such as an ArcView® file, preferably as a point theme. In analyzing the data, a WIS may assign a cell tower that lies within a respective PSAP polygon boundary to that particular PSAP for Phase I call routing. If a cell tower lies near the boundary of two PSAPs, the WIS may suggest to the involved PSAPs which PSAP should receive calls from the nearby tower. The WIS merely “suggests” because a PSAP makes the decision whether it desires to accept Phase I wireless 9-1-1 calls from a particular cell tower or cell sector.
One problem with the current approach described above is that call routing is performed based on a point feature. That is, cell towers are points (a latitude and longitude), but cell sectors are polygon features. Jurisdictional boundaries of PSAPs are also polygon features. A consequence of these differing characteristics relating to cell towers, cell sectors and jurisdictional boundaries of PSAPs is that wireless 9-1-1 calls may be routed based on cell sector for certain Phase I technological solutions. A cell tower may lie completely within the jurisdictional boundary for a first PSAP A, but one sector of the cell tower may lie almost entirely within the jurisdictional boundary for a second PSAP B lying adjacent with PSAP A. By the current approach, the recommended routing of all sectors of the exemplary tower would go to PSAP A, even though PSAP B or even another PSAP may be a more logical choice. Trial and error methods for determining a more efficient line-up between cell sectors and PSAPs is time consuming and prone to inaccuracies.
There is a need for a method and system for assigning wireless special number call touring among call answering positions for handling special number calls that provides a logical basis for determining a line-up between cell sectors and special number call answering positions.